The construction of spas is well known in the art. Typically, a spa is created by forming a wooden sub-frame made out of wood two-by-fours (or possibly a metal support frame or truss members) with an exterior wooden wanes coating or the like attached as an outer surface. Alternatively, a sub-frame made with two-by-fours or the like can be created which is coated on the outside with a form of plastic single wall panels. The wooden support frame typically then receives a formed acrylic or other type of plastic spa shell, as is well known in the art.
Existing sub-frame type spas may also include covers for preventing contamination due to environmental debris, such as leaves, pollen and the like, to prevent excess evaporation when the spa is not in use, and to act as a safety measure to prevent animals and children from falling into the water. Conventional spa covers may be fabric covered foam structures which rest atop the spa and are slid off the spa or are folded up when the spa is in use, or can be vertically movable covers that prevent contamination when resting atop the spa in a lowered position, and as a roof when in a raised position. U.S. Pat. No. 6,718,566 to Wilson and U.S. Pat. Nos. 7,600,271 and 7,614,093 to Piche et al. disclose various vertically movable covers for sub-frame type spas and lifting mechanisms therefor.
Notably, improvements in spa design and construction have eliminated the need to utilize wooden or any other type of sub-frame as a spa support structure. For example, U.S. Pat. No. 7,784,120 discloses a sub-frameless support structure for a spa that provides for cost savings, added strength and efficiency as compared to sub-frame type spas. Existing vertically movable covers, while being generally suitable for use with spas having a wooden or other sub-frame, are not readily adaptable to spas that are devoid of a sub-frame support structure.
In view of the above, there remains a need for a robust spa support structure that is capable of supporting a vertically movable cover assembly without the need for a sub-frame. There is also a need for a spa assembly having a vertically extendable cover assembly that allows access to components of the cover assembly within the support structure without removal of the spa shell or deconstruction of the spa support structure.